1. Field of the Invention
This invention relates generally to rotary ratchet mechanisms, and more particularly to a rotary ratchet mechanism which employs only a single spring for biasing driving and anti-reverse dogs toward engagement with the teeth of the wheel and returning the driving dog to a normal position.
2. Description of the Prior Art
Rotary ratchet mechanisms which provide one predetermined incremental rotation of shaft in response to each linear movement of an actuating member are well-known in the art. Prior rotary ratchet mechanisms known to the present applicant have included at least two springs for respectively biasing driving and anti-reversing dogs into engagement with respective teeth of the ratchet wheel. In one specific form of rotary ratchet mechanism known to the present applicant, a coil spring returns the actuating member and driving dog to a normal position and two leaf springs, or the opposite ends of a center-mounted leaf spring, respectively urge the driving and anti-reversing dogs into engagement with respective teeth of the wheel; however, leaf springs are subject to breakage due to fatigue and if one of the two leaf springs breaks, malfunctioning of the mechanism results.
It is accordingly desirable to provide a rotary ratchet mechanism which eliminates the leaf springs employed in prior mechanisms and utilizes only a single spring to perform all of the required biasing functions.